Modeling method and system for nuclear power plant shutdown and shutdown model

Abstract

The present application relates to a modeling method and system of nuclear power plant shutdown and shutdown model, comprising the steps of: determining modeling boundary and modeling condition; based on the modeling boundary and the modeling condition, performing structure splitting on the shutdown and shutdown fault tree model to obtain a plurality of signal fault tree modules; modeling each signal fault tree module to obtain a plurality of signal fault tree models; and assembling the plurality of signal fault tree models to form a complete shutdown and shutdown model. According to the characteristics of nuclear power unit shutdown and shutdown, the application formulates the analysis boundary condition and the modeling condition, simplifies the complex shutdown and shutdown influencing factors, simultaneously, splits the model according to the shutdown and shutdown signal, decomposes the huge shutdown and shutdown fault tree model into a plurality of independent signal fault tree modules, independently models and analyzes each signal fault tree, and finally assembles to realize the successful development of the shutdown and shutdown fault tree with the mixed multiple specialties of electromechanical instrument control and the complex system device logic relationship.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear power plants, and more particularly, to a modeling method and system of a nuclear power plant shutdown and shutdown model. BACKGROUND

[0002] With the continuous improvement of the reliability management level of nuclear power plant equipment, although the number of unplanned shutdowns and shutdowns has decreased, they still occur from time to time, and double failures leading to unplanned shutdowns and shutdowns are highlighted, which not only causes direct economic losses to nuclear power plants, but also damages the functions of safety important equipment or systems of nuclear power plants to varying degrees, directly threatening the safe and stable operation of nuclear power plants.

[0003] The nuclear power plant shutdown and shutdown model based on the fault tree can systematically identify the equipment and failure modes that cause single, double and multiple failures leading to unplanned automatic shutdowns and shutdowns, and at the same time, combined with existing equipment reliability data, realize quantitative evaluation of the unit power generation risk and equipment importance ranking, which is important for improving the existing equipment reliability management level and thus improving the performance of nuclear power plants. However, due to the size and complexity of the unplanned automatic shutdown and shutdown fault tree model, the current nuclear power plants have not carried out systematic modeling, and therefore lack a simple and fast modeling method for nuclear power plant unplanned shutdown and shutdown to realize comprehensive control of the risk of unplanned shutdown and shutdown. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a modeling method and system of a nuclear power plant shutdown and shutdown model to overcome the defects of the prior art.

[0005] The technical solution adopted by the present application to solve the technical problem is: a modeling method of a nuclear power plant shutdown and shutdown model is constructed, comprising the following steps:

[0006] determining the modeling boundary and the modeling condition;

[0007] based on the modeling boundary and the modeling condition, the shutdown and shutdown fault tree model is structurally split to obtain a plurality of signal fault tree modules;

[0008] each of the signal fault tree modules is modeled separately to obtain a plurality of signal fault tree models;

[0009] the plurality of signal fault tree models are assembled to form a complete shutdown and shutdown model.

[0010] In the modeling method of the nuclear power plant shutdown and shutdown model, the determination of the modeling boundary and the modeling condition comprises:

[0011] based on the shutdown and shutdown characteristics, a specific working condition and a device range are selected to form the modeling boundary;

[0012] Modeling conditions are formed based on the set conditions.

[0013] In the modeling method for nuclear power plant shutdown and decommissioning models described in this invention, the specific operating conditions include: reactor power operation mode, normal shutdown mode without considering steam generator cooling, normal shutdown mode with residual heat removal system cooling, maintenance shutdown mode, refueling shutdown mode, complete reactor unloading mode, and accident operating conditions.

[0014] In the modeling method for a nuclear power plant shutdown and reactor shutdown model described in this invention, the modeling conditions include:

[0015] The initial conditions for the unit were normal power operation, all equipment status and protection operation were set according to normal configuration, the operator correctly executed the instructions according to the procedure, and no maintenance measures were taken for the equipment.

[0016] In the modeling method for a nuclear power plant shutdown and reactor stoppage model described in this invention, the step of structurally decomposing the shutdown and reactor stoppage fault tree model based on the modeling boundaries and modeling conditions to obtain multiple signal fault tree modules includes:

[0017] Based on the modeling boundaries and modeling conditions, the shutdown fault tree model is split into two parts to obtain the automatic shutdown module and the automatic shutdown module.

[0018] The automatic shutdown module and the automatic shutdown module are separated to obtain a two-level split module; the two-level split module includes: a specific shutdown / shutdown signal triggering module and a shutdown / shutdown actuator malfunction module;

[0019] The specific shutdown / shutdown signal triggering module is broken down to obtain the multiple signal fault tree modules.

[0020] In the modeling method for nuclear power plant shutdown and reactor shutdown models described in this invention, the method further includes:

[0021] The malfunction module of the shutdown / stoppage actuator is split into multiple shutdown fault tree modules and multiple stoppage fault tree modules.

[0022] In the modeling method for nuclear power plant shutdown and reactor stoppage model described in this invention, the plurality of reactor stoppage fault tree modules include: reactor protection system failure module, rod control system failure module, and rod control power system failure module;

[0023] The multiple shutdown fault tree modules include: a turbine protection system failure module and a generator protection system failure module.

[0024] In the modeling method for a nuclear power plant shutdown model described in this invention, the step of individually modeling each signal fault tree module to obtain multiple signal fault tree models includes:

[0025] signal configuration and control analysis is performed on each signal fault tree module to obtain signal configuration and control information;

[0026] signal related equipment and fault mode analysis is performed on each signal fault tree module to obtain signal trigger causes;

[0027] slave equipment and fault mode analysis of signal related equipment is performed on each signal fault tree module to obtain protection signal occurrence causes;

[0028] modeling is performed according to the signal configuration and control information, the signal trigger causes and the protection signal occurrence causes of each signal fault tree module to obtain a plurality of signal fault tree models.

[0029] In the modeling method of the nuclear power plant shutdown and shutdown model, the method further comprises:

[0030] In the modeling process of each signal fault tree module, a standard fault mode database is generated;

[0031] In the modeling process of each signal fault tree module, a standard fault tree template database is generated;

[0032] The standard fault mode database and the standard fault tree template database are stored.

[0033] The application further provides a modeling system of a nuclear power plant shutdown and shutdown model, comprising:

[0034] A determination unit is configured to determine a modeling boundary and a modeling condition;

[0035] A structure splitting unit is configured to split the shutdown and shutdown fault tree model based on the modeling boundary and the modeling condition to obtain a plurality of signal fault tree modules;

[0036] A modeling unit is configured to model each signal fault tree module to obtain a plurality of signal fault tree models;

[0037] An assembly unit is configured to assemble the plurality of signal fault tree models to form a complete shutdown and shutdown model.

[0038] The modeling method and system of the nuclear power plant shutdown and shutdown model of the application have the following beneficial effects: comprising the steps of: determining the modeling boundary and the modeling condition; based on the modeling boundary and the modeling condition, performing structural splitting on the shutdown and shutdown fault tree model to obtain a plurality of signal fault tree modules; modeling each signal fault tree module to obtain a plurality of signal fault tree models; and assembling the plurality of signal fault tree models to form a complete shutdown and shutdown model. According to the characteristics of the nuclear power unit shutdown and shutdown, the application formulates the analysis boundary condition and the modeling condition, simplifies the complex shutdown and shutdown influencing factors, simultaneously, splits the model according to the shutdown and shutdown signal, disassembles the huge shutdown and shutdown fault tree model into a plurality of independent signal fault tree modules, independently models and analyzes each signal fault tree, and finally assembles to realize the successful development of the shutdown and shutdown fault tree with the mixed electromechanical instrument control of multiple professions, and the complex logical relationship of system equipment. BRIEF DESCRIPTION OF DRAWINGS

[0039] The application will be further described below in combination with the drawings and embodiments, and the drawings are as follows:

[0040] Figure 1 is a flowchart of the modeling method of the nuclear power plant shutdown and shutdown model provided by the embodiment of the application;

[0041] Figure 2 is a splitting schematic diagram of the shutdown and shutdown fault tree model provided by the embodiment of the application;

[0042] Figure 3 is a modeling flowchart of each signal fault tree model provided by the embodiment of the application;

[0043] Figure 4 is a system level process flowchart of the low-low steam generator water level shutdown signal provided by the application;

[0044] Figure 5 is a device level process flowchart of the low-low steam generator water level shutdown signal provided by the application;

[0045] Figure 6 is a support device schematic diagram of the main feedwater system pneumatic control valve provided by the application;

[0046] Figure 7 is a signal fault tree model schematic diagram of the low-low steam generator water level shutdown signal provided by the application;

[0047] Figure 8 is a structural schematic diagram of the modeling system of the nuclear power plant shutdown and shutdown model provided by the embodiment of the application. DETAILED DESCRIPTION

[0048] In order to make the technical features, objectives and effects of the present application more clearly understood, the specific embodiments of the present application will be described in detail with reference to the drawings.

[0049] In view of the current situation that there is no automatic shutdown and shutdown model in nuclear power plants to comprehensively manage the shutdown and shutdown risk of the unit, and the problem that the development process of the shutdown and shutdown model is "super huge" and "extremely complex", the present application provides a method and system for efficiently establishing a unit shutdown and shutdown model. Specifically, referring to Figure 1 The flowchart of an optional embodiment of the modeling method of the nuclear power plant shutdown and shutdown model provided by the present application is shown in

[0050] As Figure 1 shown, the modeling method of the nuclear power plant shutdown and shutdown model includes the following steps:

[0051] Step S101, determining the modeling boundary and the modeling condition.

[0052] In some embodiments, determining the modeling boundary and the modeling condition includes: selecting specific working conditions and equipment ranges to form the modeling boundary based on the shutdown and shutdown characteristics; and forming the modeling condition based on the set condition.

[0053] The specific working conditions include: reactor power operation mode, normal shutdown mode without considering steam generator cooling, normal shutdown mode of residual heat removal system cooling, maintenance shutdown mode, refueling shutdown mode, reactor complete discharge mode and accident working condition. The specific equipment specifically refers to: not considering the influence of the equipment on the mother pipe shunt on the drain, exhaust and sampling pipeline; software, pipeline, cable, cable terminal, cable joint, support hanger, structure are not in the analysis range; the bottom event hardware granularity is to the equipment level; the process equipment support source (air source, power source, cold source, etc.) is traced back to the upstream isolation switch or isolation valve boundary definition, etc.

[0054] In some embodiments, the modeling condition includes: the initial condition of the unit adopts normal power operation of the unit, all device states and protection operation are set according to the normal configuration, the operator correctly executes the instruction requirements according to the program, and no maintenance measures are taken on the equipment. That is, it is assumed that the initial condition of the unit adopts normal power operation of the unit, all device states and protection operation are set according to the normal configuration; the nuclear power plant operator can correctly execute the instruction requirements according to the program; and no maintenance measures are taken on the equipment.

[0055] Step S102, based on the modeling boundary and the modeling condition, the structure of the shutdown and shutdown fault tree model is split to obtain a plurality of signal fault tree modules.

[0056] In some embodiments, the structure splitting of the shutdown and trip fault tree model based on the modeling boundary and the modeling condition to obtain a plurality of signal fault tree modules comprises: performing first splitting of the shutdown and trip fault tree model based on the modeling boundary and the modeling condition to obtain an automatic trip module and an automatic shutdown module; performing splitting of the automatic trip module and the automatic shutdown module respectively to obtain second splitting modules; the second splitting modules comprise: a specific trip / shutdown signal triggering module and a trip / shutdown execution mechanism malfunction module; and performing splitting of the specific trip / shutdown signal triggering module to obtain a plurality of signal fault tree modules.

[0057] Further, the trip / shutdown execution mechanism malfunction module is also split in the present application to obtain a plurality of trip fault tree modules and a plurality of shutdown fault tree modules.

[0058] The plurality of trip fault tree modules comprise: a reactor protection system failure module, a rod control system failure module, and a rod control power supply system failure module; and the plurality of shutdown fault tree modules comprise: a steam turbine protection system failure module and a generator protection system failure module.

[0059] Specifically, the entire shutdown and trip fault tree model is split into an “automatic trip” part (the automatic trip module) and an “automatic shutdown” part (the automatic shutdown module), and then the split “automatic trip” part and the split “automatic shutdown” part are further split into a “specific trip / shutdown signal triggering” part (the specific trip / shutdown signal triggering module (i.e., the specific trip signal triggering module and the specific shutdown signal triggering module)) and a “trip / shutdown execution mechanism malfunction” part (the trip / shutdown execution mechanism malfunction module (i.e., the trip execution mechanism malfunction module and the shutdown execution mechanism malfunction module)). According to the trip and shutdown protection signal setting conditions of different nuclear power units, the “specific trip / shutdown signal triggering” part is split into a plurality of specific signal fault tree modules. The trip execution mechanism is split into three fault tree modules, i.e., reactor protection system failure, rod control system failure, and rod control power supply system failure. The shutdown execution mechanism is split into two fault tree modules, i.e., steam turbine protection system failure and generator protection system failure. The specific splitting schematic diagram can be referred to the shutdown and trip fault tree structure splitting diagram of FIG. 1. Figure 2

[0060] As shown in FIG. 1, the shutdown and trip fault tree model is split into an automatic trip module and an automatic shutdown module, and then the automatic trip module and the automatic shutdown module are further split into a specific trip signal triggering module, a specific shutdown signal triggering module, a trip execution mechanism malfunction module, and a shutdown execution mechanism malfunction module. Figure 2 ​As shown, during the power operation, the unit is automatically shut down and shut down. If the reactor control rod is automatically dropped during the power operation (≥1), it can be first decomposed into: stop execution mechanism malfunction module and specific stop signal triggering module, and then the specific stop signal triggering module is split, which can be decomposed into: stop signal 1 trigger, stop signal 2 trigger, stop signal… Trigger and other stop signal fault tree modules. The stop execution mechanism malfunction module is split into: reactor protection system failure (RPR logic fault), rod control system failure (RGL rod control fault), and rod control power supply system failure (RAM power supply stop); If the turbine is automatically tripped during the power operation, it can be first decomposed into: stop execution mechanism malfunction module and specific stop signal triggering module, and then the specific stop signal triggering module is split, which can be decomposed into: stop signal 2 trigger, stop signal 3 trigger, stop signal… Trigger and other stop signal fault tree modules. The stop execution mechanism malfunction module is split into: turbine protection system failure (GSE protection fault) and generator protection system failure (GPA protection fault), and then the specific stop signal triggering module is split, which can be decomposed into: stop signal 2 trigger, stop signal 3 trigger, stop signal… Trigger and other stop signal fault tree modules. The multiple stop signal fault tree modules and the multiple stop signal fault tree modules form multiple signal fault tree modules.

[0061] Step S103, modeling each signal fault tree module separately to obtain multiple signal fault tree models.

[0062] In some embodiments, as shown in Figure 3 Modeling each signal fault tree module separately to obtain multiple signal fault tree models includes:

[0063] Step S301, signal configuration and control analysis is performed on each signal fault tree module to obtain signal configuration and control information.

[0064] Specifically, for a specific protection signal, the probe and installation position of the trigger signal are first identified, and then technical data analysis (such as by querying flowchart, logic diagram, simulation diagram, wiring diagram, etc. Technical data) is performed to obtain signal configuration and control information. Among them, the signal configuration and control information can be the probe of the signal, the signal circuit, and the real process measured, process configuration, and control implementation.

[0065] Step S302, signal-related equipment and fault mode analysis is performed on each signal fault tree module to obtain signal trigger reasons.

[0066] Specifically, according to the signal process flowchart, the specific fault mode of the process equipment can be analyzed when the protection signal is triggered, and the signal trigger reason is obtained.

[0067] Step S303, slave equipment and fault mode analysis of signal-related equipment is performed on each signal fault tree module to obtain protection signal occurrence reasons.

[0068] In the embodiment of the present application, the slave device of the signal-related device refers to the support device of the signal-related device. Specifically, for the selected active process equipment (signal-related device), the power supply, control, cooling, gas source and other support conditions required for normal implementation of the function are further analyzed, and for each support condition, the entire support link device list is further identified, and specifically, the first interface device of the support system can be identified. For the support link device of the selected active process equipment, it is further analyzed which fault mode of which device will eventually cause the protection signal to trigger, and then the cause of the protection signal is determined.

[0069] Step S304, modeling according to the signal configuration and control information of each signal fault tree module, the signal trigger reason and the protection signal occurrence reason, and obtaining a plurality of signal fault tree models.

[0070] In the embodiment of the present application, by adopting the combination method of node method (direct cause) and super element method (function module), starting from the top event, combining process flow chart, instrument control logic diagram, instrument control simulation diagram, instrument control wiring diagram, electrical wiring diagram, using process equipment and fault mode screening method, support equipment and fault mode screening method of process equipment, each signal fault tree module is analyzed layer by layer, and a signal tree fault model is constructed, so that a plurality of signal fault tree models can be obtained.

[0071] In the embodiment of the present application, in step S103, a standard fault mode library of common mechanical, electrical and instrument control equipment is established, which is directly called in the device fault mode analysis link, simple and efficient, and standardized and unified, such as the standard fault mode of relay "misoperation, refusal to operate", the standard fault mode of temperature probe "upward drift, downward drift" and the like. For the common fault modes of common active equipment, a standard fault tree template is established, such as "pneumatic regulating valve regulating too large", which is called when the same type of equipment appears in different signal fault trees, so as to improve the efficiency and standardization of fault tree modeling.

[0072] Step S104, assembling the plurality of signal fault tree models to form a complete shutdown and shutdown model.

[0073] Further, in the embodiment of the present application, by constructing the complete shutdown and shutdown model, based on the visual query, systematic analysis and quantitative evaluation of the complete shutdown and shutdown model, the operation and maintenance data are fused to realize the data+model driven unit shutdown and shutdown management, and the automatic shutdown and shutdown of the unit are avoided.

[0074] Further, in some embodiments, the modeling method of the nuclear power plant shutdown and shutdown model further comprises: generating a standard fault mode database during modeling of each signal fault tree module; generating a standard fault tree template database during modeling of each signal fault tree module; and storing the standard fault mode database and the standard fault tree template database.

[0075] Specifically, during the modeling process of the complete shutdown and shutdown model, the standard fault mode database and the standard fault tree template database are formed, which can be called in subsequent modeling processes, and the model can be updated and optimized in real time during application if model problems are found.

[0076] Reference Figure 8 The modeling system of the nuclear power plant shutdown and shutdown model provided by the present application is shown in the structural diagram. The modeling system can be used to implement the modeling method of the nuclear power plant shutdown and shutdown model provided by the embodiments of the present application. Specifically, as shown in the structural diagram, Figure 8 The modeling system of the nuclear power plant shutdown and shutdown model provided by the embodiments of the present application comprises:

[0077] The determining unit 801 is configured to determine the modeling boundary and the modeling condition.

[0078] The structure splitting unit 802 is configured to split the shutdown and shutdown fault tree model based on the modeling boundary and the modeling condition, and obtain a plurality of signal fault tree modules.

[0079] The modeling unit 803 is configured to model each signal fault tree module separately, and obtain a plurality of signal fault tree models.

[0080] The assembling unit 804 is configured to assemble the plurality of signal fault tree models to form a complete shutdown and shutdown model.

[0081] The modeling method and system of the nuclear power plant shutdown and shutdown model of the present application simplify the complex shutdown and shutdown influencing factors according to the shutdown and shutdown characteristics of the nuclear power unit, analyze the boundary conditions and assumption conditions, split the large shutdown and shutdown fault tree model into a plurality of independent signal fault tree modules according to the shutdown and shutdown signals, determine the standard development process and specification for each signal fault tree through repeated practice, perform independent modeling analysis, and finally assemble to realize the successful development of the shutdown and shutdown fault tree with multiple professional mixtures and complex system device logic relationships. Based on the visualization query, systematic analysis and quantitative evaluation capability of the model, the operation and maintenance data are fused, the data+model driven unit shutdown and shutdown management application is implemented, and the automatic shutdown and shutdown of the unit is avoided.

[0082] The modeling process of the signal fault tree is described below by taking the low-low signal of the steam generator (SG) water level of a pressurized water reactor nuclear power plant as an example.

[0083] 1) Signal-related configuration and control analysis.

[0084] The direct causes of the SG low water level shutdown signal triggering include two aspects: ① malfunction of the SG water level probe or signal transmission loop leading to false signal triggering; ② the actual SG water level reaching the low threshold, causing signal triggering. The actual SG water level is determined by both the influent and effluent flow rates. Insufficient influent or excessive effluent flow will result in a low SG water level. A simplified system-level process flow diagram is shown below. Figure 4 As shown. By Figure 4 It can be seen that the SG feedwater comes directly from the main feedwater system (ARE). Insufficient feedwater can be caused not only by issues with the ARE itself, but also by malfunctions in the upstream high-pressure heater system (AHP), steam-driven feedwater pump system (APP), and electric feedwater pump system (APA). Excessive water output can be caused by excessive steam output from the new steam system (VVP) and excessive blowdown consumption from the steam generator blowdown system (APG). During normal unit operation, the total blowdown volume of the SG does not exceed 70 t / h, which is negligible compared to the feedwater flow rate (2000 t / h). Excessive VVP steam consumption is mainly due to a secondary loop rupture, which is not considered here. Therefore, the signal fault tree analysis only considers insufficient ARE feedwater leading to a low SG water level.

[0085] 2) Analysis of signal-related equipment and failure modes

[0086] Next, based on the simplified process flow diagram at the system level, we will further analyze the equipment and fault modes involved in signal triggering, including the probes and signal transmission loop equipment and fault modes that cause false signal triggering, as well as the related process equipment and fault modes that cause the parameters measured by the probes to actually reach the stack jump threshold.

[0087] To address the issue of a truly low SG water level, this study analyzes the equipment and failure modes in the relevant process systems that lead to this low SG water level, identifying the equipment-level process flow diagrams that cause the SG water level to reach the low threshold. Figure 5 As shown.

[0088] Depend on Figure 5 It can be seen that the ARE system feedwater includes main feedwater and bypass feedwater. When the unit power level is >18%Pn, feedwater regulation is performed through the main feedwater; otherwise, it is performed through the bypass feedwater. In the fault tree construction, the feedwater regulation mode can be controlled through room type events. Insufficient ARE feedwater can be caused by under-regulation of the pneumatic regulating valve in the feedwater regulation loop or erroneous closure of the upstream and downstream isolation valves.

[0089] The upstream AHP system of the ARE system includes two heat exchanger circuits to heat the feedwater. If both circuits cannot normally feed water, it will lead to insufficient feedwater for the ARE. For each heating circuit, the upstream and downstream isolation valves are mistakenly closed, and the high-pressure heater and the heat exchanger internal break will lead to insufficient feedwater for the circuit.

[0090] The upstream APP / APA feedwater pump system of the AHP includes two APP pumps and one APA pump, and two operating pumps provide feedwater. The control system keeps the pressure difference before and after the ARE regulating valve constant. If one of the two operating pump groups fails to operate, or the standby pump group fails to start, or the flow of the two operating pump groups is low, it will lead to insufficient feedwater for the APP / APA system. In addition, the pump inlet and outlet isolation valves are mistakenly closed, the pump inlet filter is blocked, and the pump inlet expansion joint leaks, which will lead to insufficient feedwater.

[0091] 3) Support equipment of active equipment and fault mode analysis

[0092] Next, for the active equipment screened out in the previous step, the support equipment (including power supply, gas supply, steam supply, cold source, control-related equipment, etc.) and fault modes that cause the functional failure of the active equipment are analyzed and sorted out.

[0093] In the SG low water level low shutdown signal fault tree, the support equipment of the ARE pneumatic regulating valve, such as Figure 6 As shown in the figure, the opening adjustment of the ARE pneumatic regulating valve requires the support of gas supply and control equipment. The control signal controls the valve opening by controlling the size of the control gas supply. Therefore, in addition to the valve body, the reasons for the small adjustment of the ARE pneumatic regulating valve also include the failure of the gas supply and control-related support equipment, such as insufficient supply of instrument air distribution system (SAR), mistakenly closed electromagnetic valve (EL1 and EL2), and small control of intelligent positioner (EP). In addition to the electromagnetic valve itself, the mistakenly closed electromagnetic valve also includes the failure of the control signal and power supply-related support equipment of the electromagnetic valve, including the malfunction of the relay and the loss of power supply module.

[0094] For each active equipment screened out in the process, the support equipment is analyzed. For some support equipment that also supports the active equipment, the support equipment is further analyzed, and the analysis is gradually performed layer by layer, and finally all devices and faults that trigger the SG low water level low signal are found.

[0095] 4) Construction of signal fault tree model

[0096] Finally, through the analysis of the signal-related transmission circuit and the process system, the signal-related equipment and fault mode analysis, the support equipment of the active equipment and the fault mode analysis, the node method (direct cause) and the super element method (functional module) are combined, starting from the top event, and gradually analyzing and deducing in the special fault tree software, and finally constructing a complete fault tree model.

[0097] According to the above analysis of the SG water level low low trip signal, a fault tree model diagram of the SG water level low low trip signal is constructed as shown in Figure 7 .

[0098] The various embodiments described in the specification are progressive in nature, and each embodiment highlights the differences from other embodiments. The same or similar parts between embodiments can be mutually referred to. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0099] The skilled person can further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0100] The steps of the method or algorithm described in combination with the embodiments disclosed herein can be directly implemented by hardware, a software module executed by a processor, or a combination of both. The software module can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0101] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it accordingly, and cannot limit the protection scope of the present application. Any equivalent changes and modifications made within the scope of the claims of the present application shall be included in the scope of the claims of the present application.

Claims

1. A modeling method for a nuclear power plant shutdown and reactor stoppage model, characterized in that, Includes the following steps: Determining the modeling boundaries and conditions includes: selecting specific operating conditions and equipment ranges to form the modeling boundaries based on shutdown and reactor shutdown characteristics, wherein the specific operating conditions include: reactor power operation mode; and forming modeling conditions based on set conditions, wherein the set conditions include: the unit's initial conditions adopting normal power operation. Based on the modeling boundaries and modeling conditions, the shutdown and reactor failure tree model is structurally decomposed to obtain multiple signal failure tree modules; Each signal fault tree module is modeled individually to obtain multiple signal fault tree models, including: performing signal configuration and control analysis on each signal fault tree module to obtain signal configuration and control information; performing signal-related equipment and fault mode analysis on each signal fault tree module to obtain signal triggering causes, wherein the signal-related equipment includes probes and signal transmission loop equipment that cause false signal triggering and process equipment that causes actual signal triggering; performing slave device and fault mode analysis on each signal fault tree module to obtain the cause of protection signal occurrence; and modeling based on the signal configuration and control information, the signal triggering causes, and the cause of protection signal occurrence of each signal fault tree module to obtain multiple signal fault tree models. The multiple signal fault tree models are assembled to form a complete shutdown and reactor shutdown model.

2. The modeling method for a nuclear power plant shutdown and reactor stoppage model according to claim 1, characterized in that, The specific operating conditions include: normal shutdown mode without considering steam generator cooling, normal shutdown mode with residual heat removal system cooling, maintenance shutdown mode, refueling shutdown mode, complete reactor unloading mode, and accident conditions.

3. The modeling method for a nuclear power plant shutdown model according to claim 1, characterized in that, The modeling conditions include: All equipment status and protection operation were set according to normal configuration, the operator correctly executed the instructions according to the procedure, and no maintenance measures were taken for the equipment.

4. The modeling method for a nuclear power plant shutdown model according to claim 1, characterized in that, Based on the modeling boundaries and modeling conditions, the shutdown and reactor failure tree model is structurally decomposed to obtain multiple signal failure tree modules, including: Based on the modeling boundaries and modeling conditions, the shutdown fault tree model is split into two parts to obtain the automatic shutdown module and the automatic shutdown module. The automatic shutdown module and the automatic shutdown module are separated to obtain a two-level split module; the two-level split module includes: a specific shutdown / shutdown signal triggering module and a shutdown / shutdown actuator malfunction module; The specific shutdown / shutdown signal triggering module is broken down to obtain the multiple signal fault tree modules.

5. The modeling method for a nuclear power plant shutdown model according to claim 4, characterized in that, The method further includes: The malfunction module of the shutdown / stoppage actuator is split into multiple shutdown fault tree modules and multiple stoppage fault tree modules.

6. The modeling method for a nuclear power plant shutdown model according to claim 5, characterized in that, The multiple reactor shutdown fault tree modules include: reactor protection system failure module, rod control system failure module, and rod control power system failure module; The multiple shutdown fault tree modules include: a turbine protection system failure module and a generator protection system failure module.

7. The modeling method for a nuclear power plant shutdown model according to claim 1, characterized in that, The method further includes: During the modeling process of each of the aforementioned signal fault tree modules, a standard fault mode database is generated; During the modeling process of each of the aforementioned signal fault tree modules, a standard fault tree template database is generated; The standard fault mode database and the standard fault template database are stored.

8. A modeling system for a nuclear power plant shutdown and reactor stoppage model, characterized in that, include: Define the elements to determine the modeling boundaries and modeling conditions; The structural decomposition unit is used to decompose the shutdown and reactor failure tree model based on the modeling boundary and modeling conditions to obtain multiple signal failure tree modules; A modeling unit is used to model each of the signal fault tree modules individually to obtain multiple signal fault tree models; An assembly unit is used to assemble the multiple signal fault tree models to form a complete shutdown and stack stop model; The determining unit is specifically used for: selecting specific operating conditions and equipment ranges to form modeling boundaries based on shutdown and reactor shutdown characteristics, wherein the specific operating conditions include: reactor power operation mode; and forming modeling conditions based on set conditions, wherein the set conditions include: the unit's initial conditions adopt the unit's normal power operation. The modeling unit is specifically used for: performing signal configuration and control analysis on each signal fault tree module to obtain signal configuration and control information; performing signal-related equipment and fault mode analysis on each signal fault tree module to obtain the signal triggering cause, wherein the signal-related equipment includes probes and signal transmission loop equipment that cause false signal triggering and process equipment that causes actual signal triggering; performing slave device and fault mode analysis on each signal fault tree module to obtain the cause of protection signal occurrence; and performing modeling based on the signal configuration and control information, the signal triggering cause, and the cause of protection signal occurrence of each signal fault tree module to obtain multiple signal fault tree models.

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